Reply To: Automatically resize thumbnails

Try this:

open Appearance -> Editor -> functions.php

on line 51 you will see

add_image_size('excerpt-thumbnail', 200, 140, true); // Sets Index Page Thumbnails

Replace it with

add_image_size('excerpt-thumbnail', 200, 140, false); // Sets Index Page Thumbnails

We just changed true to false.

true: images will be cropped : this is the default
false: images will be scaled : can cause uneven sizes if your parent images are of different sizes.